Flange, Raised Face 4" 150 Carbon Steel X 5" Storz
https://www.wfrfire.com/shop/p-10107-flange-raised-face-4-150-carbon-steel-x-5-storz-10107
https://www.wfrfire.com/web/image/product.template/10107/image_1920?unique=f1b267e
Special order. Not returnable